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@justinyoo

justinyoo/01-callback-1.cs

Last active Jan 20, 2021
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WebSub to EventGrid via CloudEvents and Beyond
[FunctionName("CallbackAsync")]
public async Task<IActionResult> CallbackAsync(
[HttpTrigger(AuthorizationLevel.Function, "GET", "POST", Route = "callback")] HttpRequest req,
ILogger log)
{
if (HttpMethods.IsGet(req.Method))
{
string challenge = req.Query["hub.challenge"];
var result = new ObjectResult(challenge) { StatusCode = 200 };
return result;
}
<feed xmlns:yt="http://www.youtube.com/xml/schemas/2015" xmlns="http://www.w3.org/2005/Atom">
<link rel="hub" href="https://pubsubhubbub.appspot.com"/>
<link rel="self" href="https://www.youtube.com/xml/feeds/videos.xml?channel_id=[channel_id]"/>
<title>YouTube video feed</title>
<updated>2021-01-27T07:00:00.123456789+00:00</updated>
<entry>
<id>yt:video:[video_id]</id>
<yt:videoId>[video_id]</yt:videoId>
<yt:channelId>[channel_id]</yt:channelId>
<title>hello world</title>
<link rel="alternate" href="http://www.youtube.com/watch?v=<video_id>"/>
<author>
<name>My Channel</name>
<uri>http://www.youtube.com/channel/[channel_id]</uri>
</author>
<published>2021-01-27T07:00:00+00:00</published>
<updated>2021-01-27T07:00:00.123456789+00:00</updated>
</entry>
</feed>
var payload = default(string);
using (var reader = new StreamReader(req.Body))
{
payload = await reader.ReadToEndAsync().ConfigureAwait(false);
}
Link: <https://pubsubhubbub.appspot.com>; rel=hub, <https://www.youtube.com/xml/feeds/videos.xml?channel_id=[channel_id]>; rel=self
var headers = req.Headers.ToDictionary(p => p.Key, p => string.Join("|", p.Value));
var links = headers["Link"]
.Split(new[] { "," }, StringSplitOptions.RemoveEmptyEntries)
.Select(p => p.Trim().Split(new[] { ";" }, StringSplitOptions.RemoveEmptyEntries))
.ToDictionary(p => p.Last().Trim(), p => p.First().Trim().Replace("<", string.Empty).Replace(">", string.Empty));
var source = links["rel=self"];
var type = "com.youtube.video.published";
var contentType = "application/cloudevents+json";
var @event = new CloudEvent(source, type, payload, contentType);
var events = new List<CloudEvent>() { @event };
var topicEndpoint = new Uri("https://<eventgrid_name>.<location>-<random_number>.eventgrid.azure.net/api/events");
var credential = new AzureKeyCredential("eventgrid_topic_access_key");
var publisher = new EventGridPublisherClient(topicEndpoint, credential);
var response = await publisher.SendEventsAsync(events).ConfigureAwait(false);
return new StatusCodeResult(response.Status);
}
{
"id": "c2e9b2d1-802c-429d-b772-046230a9261e",
"source": "https://www.youtube.com/xml/feeds/videos.xml?channel_id=<channel_id>",
"data": "<websub_xml_data>",
"type": "com.youtube.video.published",
"time": "2021-01-27T07:00:00.123456Z",
"specversion": "1.0",
"datacontenttype": "application/cloudevents+json",
"traceparent": "00-37d33dfa0d909047b8215349776d7268-809f0432fbdfd94b-00"
}
{
"channelId": "<channel_id>",
"videoId": "<video_id>",
"title": "hello world",
"description": "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis malesuada.",
"link": "https://www.youtube.com/watch?v=<video_id>",
"thumbnailLink": "https://i.ytimg.com/vi/<video_id>/maxresdefault.jpg",
"datePublished": "2021-01-27T07:00:00+00:00",
"dateUpdated": "2021-01-27T07:00:00+00:00"
}
{
"id": "4cee6312-6584-462f-a8c0-c3d5d0cbfcb1",
"specversion": "1.0",
"source": "https://www.youtube.com/xml/feeds/videos.xml?channel_id=<channel_id>",
"type": "com.youtube.video.converted",
"time": "2021-01-16T05:21:23.9068402Z",
"datacontenttype": "application/cloudevents+json",
"data": {
"channelId": "<channel_id>",
"videoId": "<video_id>",
"title": "hello world",
"description": "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis malesuada.",
"link": "https://www.youtube.com/watch?v=<video_id>",
"thumbnailLink": "https://i.ytimg.com/vi/<video_id>/maxresdefault.jpg",
"datePublished": "2021-01-27T07:00:00+00:00",
"dateUpdated": "2021-01-27T07:00:00+00:00"
}
}
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